Telling the diagnosis to patients with Alzheimer's disease. Relatives should act as proxy for patient.
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Biomedical subjects
Publications and source records attributed to R C Barnes.
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Most cases of babesiosis reported in the United States have been tickborne and caused by Babesia microti, the etiologic agent of all previously described transfusion-transmitted cases. A 76-year-old man with the first recognized case of transfusion-transmitted infection with the recently identified WA1-type Babesia parasite is described. The subject received multiple blood transfusions in 1994. Indirect immunofluorescent antibody testing of serum from 57 blood donors implicated a 34-year-old man (WA1 titer, 1:65,536) whose donation had been used for packed red cells. Isolates of the organisms that infected the recipient and the donor, both of whom were spleen-intact residents of Washington State, were obtained by hamster inoculation. The DNA sequence of a 536-bp region of the nuclear small subunit-rRNA gene of both isolates was identical to that of WA1 (isolated in 1991 from the index WA1 case-patient). Effective measures for preventing transmission of babesiosis by blood transfusion are needed.
BACKGROUND: ECT is rarely used as a prophylactic treatment. A 74-year-old woman with unstable bipolar affective disorder receiving maintenance ECT presented a unique opportunity to measure the cognitive effects of continuing ECT. METHOD: A single case report with serial psychometric testing during over 400 ECT treatments as a single maintenance treatment. RESULTS: Serial testing did not demonstrate progressive cognitive deterioration, but consistent cognitive deficits typical of acute treatment were evident. The degree of cognitive difficulty may be related to the frequency of treatment. CONCLUSIONS: Maintenance ECT can be an effective prophylactic treatment for selected patients. Cognitive effects would appear to be no greater than with acute treatment and seem to be non-progressive.
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OBJECTIVE: To examine the use of accident and emergency (A&E) services by the homeless, with particular reference to the use of psychiatric services generated by this attendance. METHODS: A retrospective study of attendance registers at a large A&E department over an eight year period, during which there were 566 separate attendances by homeless patients out of a total of 421 237 adult attendances (1.3 per 1000). RESULTS: There was no significant change in rates of attendances over the eight year period (P = 0.41), in the broad demographic details of the groups, or in the use of psychiatric services. CONCLUSIONS: There has been no significant increase in the use of A&E services by homeless people in the population studied over the eight year period. Several possible explanations for this are given.
A novel serpin gene has been isolated, cloned and sequenced. A PCR amplified fragment of the gene was originally identified from human genomic DNA, and the full-length cDNA was subsequently isolated from HeLa cells and sequenced. The novel serpin is very high in protein sequence similarity (91.8%) to the squamous cell carcinoma antigen (SCCA), but contains substantial differences in the reactive site loop sequence, including a different amino acid (leucine) in the P1 position. The gene product, named leupin, is expressed in HeLa cells, SKGIIIa cells and human placenta. The protein has a predicted M(r) of 44,857 and an isoelectric point of 6.04 which is consistent with the more acidic form of SCCA associated with squamous cell carcinomas.
Methylxanthines are best known as phosphodiesterase inhibitors that cause a rise in intracellular cAMP. One would expect the two methylxanthines, caffeine and pentoxifylline, to have similar actions on neutrophils (PMN). However, caffeine stimulated and pentoxifylline inhibited PMN oxidative activity. Micromolar concentrations of pentoxifylline decreased native and recombinant tumor necrosis factor-alpha (TNF alpha)-primed formyl met-leu-phe (fMLP)-stimulated PMN chemiluminescence, superoxide production and myeloperoxidase (MPO) release. In contrast, equal concentrations of caffeine increased chemiluminescence and MPO release with no effect on superoxide production. These activities of the methylxanthines were only observed in the presence of physiological concentrations of adenosine, and were abolished by the treatment of the PMN with adenosine deaminase. The activities of adenosine, pentoxifylline and caffeine on PMN activity could not be readily explained by changes in PMN [cAMP]. Thus for TNF alpha-primed PMN, pentoxifylline decreases PMN activity by enhancing the effect of adenosine on degranulation and superoxide production; whereas caffeine increases PMN activity by counteracting the effect of adenosine on degranulation.
Diagnosis of infection caused by Chlamydia pneumoniae, a newly recognized respiratory pathogen, has proved difficult. Between July 1987 and April 1988, culture and serologic tests for C. pneumoniae were done on specimens from 49 patients with pneumonia seen at an Atlanta hospital emergency room. Cultures from 3 patients (6%) grew C. pneumoniae. Genus-specific Chlamydia complement fixation titers and microimmunofluorescence titers for C. pneumoniae were suggestive of acute infection in all 3 culture-positive patients. Three other patients had evidence of acute disease by published criteria for antibody titers. Most studies of C. pneumonia have not had culture-proven cases; the 6% rate of positive cultures in this study support the role of C. pneumoniae as a cause of pneumonia. More widespread availability of simplified culture systems for C. pneumoniae is needed. Caution should be used when interpreting serologic tests in the absence of culture confirmation.
OBJECTIVE: To evaluate the efficacy of a 3-week regimen of erythromycin for treatment of persistent or recurrent nongonococcal urethritis in men. DESIGN: A prospective, randomized, double-blind trial with follow-up at 2, 4, and 8 weeks after enrollment. PATIENTS: Seventy-seven evaluable men with objective evidence of nongonococcal urethritis (36 in the erythromycin group and 41 in the placebo group) with a mean age of 28 years, a median duration of urethritis of 3 months, and a median number of three previous antimicrobial regimens. INTERVENTION: Erythromycin, 500 mg, or placebo four times daily for 3 weeks. RESULTS: After 2 weeks of treatment, urethral symptoms resolved in 13 of 25 erythromycin-treated patients compared with 8 of 34 placebo-treated patients (P = 0.03). Erythromycin also resulted in more frequent resolution of urethral discharge and leukocytosis at all visits compared with placebo but these differences were not statistically significant. First-voided urine leukocyte counts decreased, however, by a median of 89% (95% CI, -96% to -67%) in the erythromycin group compared with 23% (CI, -73% to 83%) in the placebo group after treatment (P = 0.02 for the difference in changes). Further, in men with prostatic inflammation, urinary leukocyte counts decreased by a median of 94% (CI, -99% to -83%) after treatment in erythromycin-treated patients compared with a 46% increase (CI, -57% to 290%) in placebo-treated patients (P = 0.0003 for the difference in changes). CONCLUSION: A 3-week regimen of erythromycin was more effective than placebo in improving symptoms and in reducing pyuria in men with persistent or recurrent nongonococcal urethritis, especially among men with prostatic inflammation.
The pathogenic events that precede Chlamydia trachomatis salpingitis in the human fallopian tube have not been fully described. We used a model of human fallopian tubes in organ culture (HFTOC) infected with strain E/UW-5/CX of C. trachomatis to study these events. The model supported sustained C. trachomatis infection as demonstrated by recovery of viable C. trachomatis from medium and tissue over 5-7 d. However, the level of infectivity was low. Maximal infection occurred at 72 h after initial inoculation. In contrast to gonococcal infection of the HFTOC, C. trachomatis did not damage overall ciliary function of HFTOC. However, a local direct cytotoxic effect characterized by loss of microvilli and disruption of cell junctions was noted when multiple chlamydial elementary bodies attached to mucosal cells. Beginning at 24 h, and continuing throughout the course of C. trachomatis infection of HFTOC, ruptured epithelial cells releasing elementary bodies were noted. Chlamydial inclusions were seen in the mucosa by 72 h in approximately 6% of both ciliated and nonciliated epithelial cells. Mucosal inclusions contained all forms of the C. trachomatis developmental cycle. These data suggest that factors present in the human fallopian tube may limit susceptibility to chlamydial infection but support the use of the HFTOC model in the study of the pathogenesis of C. trachomatis salpingitis.
We examined the number of Chlamydia trachomatis inclusions produced in the initial passage of cell cultures of endocervical specimens from 1,231 women with positive chlamydial cultures who attended a sexually transmitted diseases clinic. Youth, white race, oral contraceptive use, and concurrent infection by Neisseria gonorrhoeae were associated with high chlamydial inclusion counts. Youth, white race, and oral contraceptive use were independent determinants of a high chlamydial inclusion count in women without concurrent gonorrhea but not in women with gonorrhea. Results of our study suggest that the degree of chlamydial excretion from the infected cervix may be influenced by characteristics of the patient being tested and may affect the ability to detect C. trachomatis in different patient groups.
We compared the performance of a commercial enzyme immunoassay (EIA) (Chlamydiazyme; Abbott Diagnostics, North Chicago, Ill.) with that of cell culture for the detection of Chlamydia trachomatis cervical infection in 1,417 women attending public health clinics. Confirmatory chlamydial testing by a direct fluorescent-antibody test (MicroTrak; Syva Co., Palo Alto, Calif.) was performed on specimens from women who had positive EIAs. Overall, only 57% of women who had a positive chlamydial test by cell culture were also positive by EIA. We noted a strong association between the number of chlamydial inclusions in cell culture and a positive EIA outcome. The proportion of culture-positive women who also had a positive EIA declined with age and a history of previous sexually transmitted disease and increased among oral contraceptive users. The results of direct fluorescent-antibody confirmatory testing suggested that cell culture was also insensitive for the detection of C. trachomatis infection. Our observations demonstrate that the performance of the chlamydial EIA may vary greatly with individual patient characteristics and that the utility of EIA as a screening test may be limited, especially in older women.
A population-based study of the sero-epidemiology of chlamydia was performed among a nationally representative sample of 760 Costa Rican women aged 25 to 59 years. Interviews and sera collection were completed between September 1984 and February 1985. The overall seroprevalence of chlamydial antibodies among these women was 56.1%. Women 25 to 39 years of age had a seroprevalence of 51.1%, while women 40 to 59 years of age had a seroprevalence of 64.2%. Women who reported no prior sexual activity had a seroprevalence rate of 48.6%, compared with a seroprevalence rate of 80.7% among women who reported three or more lifetime sexual partners. The geometric mean titre (GMT) of seropositive women ranged from 34.4 among the women who reported no prior sexual activity to 155.0 among the women with three or more lifetime sexual partners. Sero-positivity was more consistently associated with sexual activity than with age. Women with serological evidence of past Herpes simplex virus type 2 (HSV-2) or syphilis infection were more likely to be seropositive than were women without evidence of exposure to these sexually transmitted diseases, even when controlled for age and the number of lifetime sexual partners. The seropositivity among never sexually active women indicates the probable presence of Chlamydia pneumoniae infections, while the high seroprevalence of chlamydial antibodies among the sexually active women suggests that sexually transmitted Chlamydia trachomatis infections represent a public health problem not previously quantified in Costa Rica. Further seroepidemiological and/or culture studies are warranted to determine the incidence and prevalence of sexually transmitted chlamydial infection among men and younger women.
Chlamydia trachomatis is a human pathogen that causes ocular disease (trachoma and inclusion conjunctivitis), genital disease (cervicitis, urethritis, salpingitis, and lymphogranuloma venereum), and respiratory disease (infant pneumonitis). Respiratory chlamydioses also occur with infection by avian strains of C. psittaci or infection by the newly described TWAR agent. Diagnosis of most acute C. trachomatis infections relies on detection of the infecting agent by cell culture, fluorescent antibody, immunoassay, cytopathologic, or nucleic acid hybridization methods. Individual non-culture tests for C. trachomatis are less sensitive and specific than the best chlamydial cell culture system but offer the advantages of reduced technology and simple transport of clinical specimens. Currently available nonculture tests for C. trachomatis perform adequately as screening tests in populations in which the prevalence of infection is greater than 10%. A negative culture or nonculture test for C. trachomatis does not, however, exclude infection. The predictive value of a positive nonculture test may be unsatisfactory when populations of low infection prevalence are tested. Tests that detect antibody responses to chlamydial infection have limited utility in diagnosis of acute chlamydial infection because of the high prevalence of persistent antibody in healthy adults and the cross-reactivity due to infection by the highly prevalent C. trachomatis and TWAR agents. Assays for changes in antibody titer to the chlamydial genus antigen are used for the diagnosis of respiratory chlamydioses. A single serum sample that is negative for chlamydial antibody excludes the diagnosis of lymphogranuloma venereum.
We used a double-label immunofluorescence assay to examine the ability of Chlamydia trachomatis serovar F to infect and develop within HeLa 229 cells previously infected with serovar E. No exclusion to superinfection occurred for up to 24 h following infection by serovar E. The percentage of HeLa cells infected in cultures inoculated with both strains was identical to that of cells in cultures inoculated with one strain as a control. Organisms of both serovars were located within the same intracellular inclusion in 88 to 95% of HeLa cells infected with both serovars. The proportion of superinfected HeLa cells containing both strains in separate inclusions increased when there was exposure to inhibitors of cytoskeletal structure and transport. We used this inhibition to demonstrate that fusion of C. trachomatis phagosomes occurs throughout the developmental cycle.
Recent studies suggest that a group of Chlamydia strains known as TWAR, which are now proposed to be a new species called Chlamydia pneumoniae, may be a frequent cause of respiratory disease in the United States and many other countries. Current serotesting methods do not allow rapid screening of large numbers of samples to distinguish C. trachomatis exposure from C. pneumoniae exposure. We developed an enzyme immunoassay to decrease cross-reactivity between immunoglobulin G antibodies reactive with C. trachomatis and C. pneumoniae. Elementary bodies of C. trachomatis or C. pneumoniae were treated with a detergent-chelating solution to decrease the reactivity of the common lipopolysaccharide antigens. Sera from four groups of patients, totaling 143 persons, were tested by this assay. The prevalences of titers of greater than or equal to 128 to C. trachomatis and C. pneumoniae, respectively, were as follows: (i) for 23 women seropositive for C. trachomatis by the microimmunofluorescence test, 21 (91%) and 18 (78%); (ii) for 50 adult blood donors, 13 (26%) and 39 (78%); (iii) for 40 sexually transmitted disease clinic patients, 20 (50%) and 32 (80%); (iv) for 30 healthy children 5 to 7 years old, 0 (0%) and 8 (27%). Western blots (immunoblots) of each antigen corroborated the differential reactivity of C. trachomatis-positive, C. pneumoniae-negative and C. trachomatis-negative, C. pneumoniae-positive serum samples. Western blots of serum samples from rabbits immunized with either C. trachomatis or C. pneumoniae elementary bodies revealed at least two protein bands (30 and 80 kilodaltons) which appeared to represent unique C. pneumoniae antigens.
The 115,000-molecular-weight antigen of Trichomonas vaginalis was characterized using monoclonal antibodies developed to three different strains of T. vaginalis and one strain of Tritrichomonas foetus. The antigen was found to be present on all strains or isolates of T. vaginalis examined and was demonstrated to be located on the external surface plasma membrane by agglutination assays and complement-mediated lysis assays. Characteristics of the antigen were assessed with a proteolytic enzyme and periodate oxidation. Periodate treatment of whole T. vaginalis abrogated binding for eight antibodies while use of pronase-treated antigen resulted in loss of antibody binding for two different antibodies. Screening of 19 axenized clinical isolates of T. vaginalis and one strain each of T. foetus and Giardia lamblia with type-specific antibodies delineated three major groups of T. vaginalis based on antigenic specificities (epitope distributions) within the 115,000-molecular-weight antigen. In addition, one epitope of the 115,000-molecular-weight antigen was found only on the immunizing strain. Two epitopes were present on all T. vaginalis isolates as well as T. foetus and G. lamblia. One epitope was common to all T. vaginalis except one. A minimum of six different epitopes of the 115,000-molecular-weight antigen were identified. Antigens purified with type-specific or "common" monoclonal antibodies shared the same partial peptide maps demonstrating relatedness.
Four hundred and seventy-three men and women at high risk for sexually transmitted disease were tested for the presence of Chlamydia trachomatis in the urethra or the endocervix. Four groups were involved in this multicenter study of two direct fluorescent-antibody microscopy tests, Kallestad Pathfinder and Syva Microtrak, compared with culture techniques. Results from the test sites indicated that there was no significant difference overall in the sensitivity and specificity of the two test kits. However, there was some interlaboratory variation seen in the sensitivity of the microscopy, but little difference in the specificity. Either kit could be an effective screening method for C. trachomatis in high-risk populations.